RE: [openjms-user] NullPointer during OnMessage() call

[Tim A. <tm...@ne...>]

Are you deregistering the listener at any stage,
or closing the TopicSubscriber?

I'm guessing that there are multiple messages queued
for the subscriber, and there is a race condition between
the listener being removed and the server sending a message
to it.
If you are using setMessageListener(null), this must be
invoked within the same thread of control as that currently
using the Session instance i.e, if onMessage() is currently
being called, another thread can't invoke setMessageListener(null).

-Tim


> -----Original Message-----
> From: ope...@li...
> [mailto:ope...@li...]On Behalf Of J Aaron
> Farr
> Sent: Tuesday, 16 December 2003 3:38 AM
> To: ope...@li...
> Subject: [openjms-user] NullPointer during OnMessage() call
> 
> 
> Hello.
> 
> I was previously running OpenJMS 0.7.5 but ran into bug #788029.  
> So I moved to
> using 0.7.6-rc3, but now I have a new bug which behaves much like 
> the last.  It
> occurs on OnMessage() not on connect.  The client is a durable 
> subscriber to a
> topic and is running under JRE 1.2.  I've tested some other 
> clients and cannot
> reproduce the bug in them (yet).  Just wondering if anyone could 
> even give me an
> idea as to were to look for this one.  Stack trace (appears in 
> client window) is
> included below.
> 
> 11:02:56.061 ERROR [Scheduler-Worker-0] - java.lang.NullPointerException
> java.lang.NullPointerException
>         at 
> sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknow
> n Source)
>         at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
>         at sun.rmi.server.UnicastRef.invoke(Unknown Source)
>         at 
> org.exolab.jms.client.rmi.RmiJmsSessionStub_Stub.onMessage(Unknown So
> urce)
>         at 
> org.exolab.jms.server.rmi.RmiJmsServerSession.onMessage(RmiJmsServerS
> ession.java:569)
>         at 
> org.exolab.jms.server.JmsServerSession.onMessage(JmsServerSession.jav
> a:942)
>         at 
> org.exolab.jms.messagemgr.TopicConsumerEndpoint.deliverMessages(Topic
> ConsumerEndpoint.java:193)
>         at 
> org.exolab.jms.messagemgr.ConsumerEndpoint.run(ConsumerEndpoint.java:
> 425)
>         at 
> org.exolab.core.threadPool.ThreadPoolWorker.runIt(ThreadPoolWorker.ja
> va:191)
>         at 
> org.exolab.core.threadPool.ThreadPoolWorker.runWork(ThreadPoolWorker.
> java:178)
>         at 
> org.exolab.core.threadPool.ThreadPoolWorker.access$000(ThreadPoolWork
> er.java:67)
>         at 
> org.exolab.core.threadPool.ThreadPoolWorker$1.run(ThreadPoolWorker.ja
> va:122)
>         at java.lang.Thread.run(Unknown Source)
> 
> 
> Thanks!
> 
> ---
>   jaaron      <http://jadetower.org>
> 
> 
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